3GPP, which is a mobile communication standardization organization, has developed an LTE system standard as a next-generation mobile communication standard. Also, the development of the LTE-Advanced system standard as an extension of the LTE standard is under way to satisfy International Mobile Telecommunication (IMT)-Advanced system requirements proposed by the International Telecommunication Union-Radio communication Sector (ITU-R).
While the LTE standard supports a maximum radio bandwidth of 20 MHz, the LTE-Advanced standard uses bandwidth aggregation (carrier aggregation) to support a maximum bandwidth of 100 MHz. Thus, in the LTE-Advanced standard, the bandwidth of 100 MHz is divided into component carriers (CCs), each of which has a maximum bandwidth of 20 MHz, and a base station may communicate with a terminal by simultaneously using a plurality of carriers.
The terminal, which supports multicarrier communication, uses a plurality of radio channels in a broad band. The wider a frequency bandwidth for use in communication, the higher the power consumption. Therefore, the terminal of the LTE-Advanced system is configured to activate and use multiple carriers only when traffic is high and to perform communication using only a single carrier when traffic is low.
On the other hand, when a secondary carrier is configured and operated in the multicarrier environment, a secondary carrier deactivation procedure and a discontinuous reception (DRX) procedure should be stably controlled, and thus a management state is not consistent between the base station and the terminal. In addition, when the deactivation procedure is performed, a hybrid automatic repeat request (HARQ) retransmission procedure to be performed in the terminal should be managed according to a deactivation state.